The primary goal of this research project is to develop and exploit pericyclic and related reactions of electron deficient imines and iminium compounds within the general context of natural product synthesis. It is likely that useful new synthetic methodology applicable to the preparation of nitrogen heterocycles and other nitrogen-containing compounds will involve from these studies. This methodology should prove valuable to synthetic chemists in the pharmaceutical industry and others working in health-related fields. ln particular, we plan to develop short and efficient chiral total syntheses of the potent antitumor compounds narciclasine and neplanocin A using this methodology. Narciclasine is a member of the Amaryllidaceae alkaloid group. This compound and its analogs show significant cytostatic activity. Neplanocin A is a nucleoside analog which has a carbocyclic ring in place of ribose. It and its congeners, such as aristeromycin, have strong antitumor and antiviral properties. In addition, we will further explore the scope of our methodology by its application to a diverse and challenging group of heterocyclic structures. Included are the unusual antifungal alkaloids papuamine and/or haliclonadiamine produced by a marine sponge. Other targets include the Ergot alkaloids lysergic acid and paspiclavine which we hope to prepare by short, stereocontrolled routes. Another target which will test our methodology is the morphinan structure. This molecule will be prepared in a chiral synthesis from mandelic acid. Hopefully the approach can eventually be applied to more complex morphine alkaloids. lt is our intention to improve upon existing syntheses in the above cases in terms of both efficiency and stereoselectivity.